Since its invasion in the mid-1980s, Aedes albopictus has become one of the most common man-biting mosquitoes in much of its new range (e.g., southeastern USA, Brazil, southern Europe, West Africa). New arrivals (e.g., California in 2001) are expected, with unknown consequences for human health. In 2001, during a dengue outbreak in Hawaii, Ae. albopictus was the only known vector, and is now an important transmitter of LaCrosse encephalitis virus in the southeastern USA. During the 2002 epidemic of West Nile virus in the USA, Ae. albopictus was recovered infected in 11 States and the DC and is now regarded as an important bridge vector of WNV. Thus, it is increasingly clear that understanding of invasion processes may be crucial for accurate assessment of new health risks. The overall goal of this project is to understand the ecology of invasions by Ae. albopictus and to use this understanding to predict the consequences for transmission of arboviral disease, especially for dengue. Specific Aim 1 experimentally tests four hypotheses about the role of interspecific competition in establishments of the invader and coexistence with or exclusion of resident species that co-occupy containers with Ae. albopictus, including Culex pipiens Complex mosquitoes in WNV areas and Ae. aegypti in Florida. Outcomes of interspecific competition are tested in the context of variations in (i) geography, (ii) resource type, (iii) competition mechanism (interference vs resource), and (iv) the aerial environment. Specific Aim 2 connects the ecological research to public health by experimentally assessing the effects of larval competition on dengue transmission. Specific Aim 3 determines the role of predation in post-invasion establishments of Ae. albopictus. Laboratory and field experiments and time-series analyses of long-term census records test model-supported hypotheses that predict differential predation upon Ae. albopictus facilitates coexistence with resident container mosquito species. Experiments will also detect costs and benefits of behavioral responses to predators, the evolution of anti-predator behaviors in Ae. albopictus, and whether predators can act as a barrier to invasion. Specific Aim 4 tests in south Florida the hypothesis that distributions and abundances of Ae. albopictus and Ae. aegypti can be predicted by quantifiable habitat measures. Blood meal identifications and sugar content of wild-caught specimens will determine vertebrate hosts and nectar feeding, and effects of blood and sugar on adult fitness will be evaluated experimentally.